This invention relates to weight sensing systems for article transporting conveyors and to associated calibration systems.
Weighing systems for conveyor assemblies that transport articles along a specified path are well known. Because of the prolonged and continual operation of such weighing systems, recalibration is often required in order to maintain consistent and accurate weight measurements. For many calibration systems, it is necessary to temporarily interrupt the operation of the conveyor in order facilitate a calibration event, often resulting in recalibration of the weighing system. This checking procedure not only required the attention of personnel but also involved a loss of production time because of the interruption in conveyor operation. Other calibration systems do not require interruption of the conveyer but require an interruption of the operation of the weighing system, which is unfortunate because it prevents the weighing system from weighing material on the conveyor. Given these and other deficiencies in the art, the need for certain new and useful improvements is evident.
The above problems and others are at least partially solved and the above purposes and others realized in a first embodiment of the invention, which is characterized by a new and novel combination consisting of a weighing system that is capable of continually sensing load against a continuously moving conveyor and a calibration system for the weighing system that is capable of applying a reference load to the weighing system without interrupting the ability of the weighing system to sense load against the conveyor. In a preferred embodiment, the weighing system consists of a pivoted scale engaging the conveyor and a sensor that is capable of producing load stimulus in response to displacement of the pivoted scale by load applied against the conveyor. The calibration system consists of a reference load capable of being displaced and the sensor capable of producing test load stimulus in response to displacement of the pivoted scale by load applied against the conveyor and displacement of the reference load. A pivoted test beam supports the reference load, which is capable of pivoting between a first position and a second position displacing the reference load. An engine is associated with the pivoted test beam and is movable between a first condition corresponding to the first position of the test beam and a second condition corresponding to the second position of the test beam. Preferably, the invention is furnished with storage maintaining load stimulus data from the sensor commensurate with load applied to the conveyor and a test load stimulus data from the sensor commensurate with a combination of load applied to the conveyor and displacement of the reference load, and a controller that is capable of comparing the load stimulus data to the test load stimulus data and adjusting the weighing system if the comparison of the load stimulus data and the test load stimulus data is unacceptable.
In a conveyor continuously moving material, the material applying load to the conveyor, another embodiment of the invention proposes a weighing system that is capable of continually sensing load against the conveyor and a calibration system for the weighing system that is capable of applying a reference load to the weighing system without interrupting the ability of the weighing system to sense. load against the conveyor. In this preferred embodiment, the weighing system consists of a pivoted scale engaging the conveyor and a sensor that is capable of producing load stimulus in response to displacement of the pivoted scale by load applied against the conveyor. The calibration system consists of a reference load capable of being displaced and the sensor capable of producing test load stimulus in response to displacement of the pivoted scale by load applied against the conveyor and displacement of the reference load. A pivoted test beam supports the reference load, which is capable of pivoting between a first position and a second position displacing the reference load. An engine is associated with the pivoted test beam and is movable between a first condition corresponding to the first position of the test beam and a second condition corresponding to the second position of the test beam. Preferably, the instant embodiment of invention is furnished with storage maintaining load stimulus data from the sensor commensurate with load applied to the conveyor and a test load stimulus data from the sensor commensurate with a combination of load applied to the conveyor and displacement of the reference load, and a controller that is capable of comparing the load stimulus data to the test load stimulus data and adjusting the weighing system if the comparison of the load stimulus data and the test load stimulus data is unacceptable.
In yet another preferred embodiment the invention consists of a conveyor, a weighing system consisting of a load sensor and a scale displaced by the conveyor so as to act on the load sensor, and a reference load capable of being displaced so as to act on the load sensor. In this embodiment, a pivoted test beam supports the reference load, which is movable between a first position and a second position displacing the reference load. An engine is associated with the pivoted test beam and is movable between a first condition corresponding to the first position of the test beam and a second condition corresponding to the second position of the test beam. Preferably, this embodiment of the invention is further furnished with storage maintaining load stimulus data from the load sensor commensurate with load applied to the conveyor and a test load stimulus data from the load sensor commensurate with a combination of load applied to the conveyor and displacement of the reference load, and a controller capable of comparing the load stimulus data to the test load stimulus data and adjusting the weighing system if the comparison of the load stimulus data and the test load stimulus data is unacceptable.
Consistent with the foregoing the invention also contemplates associated methods. In a preferred embodiment, an exemplary method of the invention is carried out in a conveyor and a weighing system that is capable of continually sensing load against the conveyor and generating load stimulus commensurate with the load against the conveyor. The method consists of applying a reference load to the weighing system, generating test load stimulus commensurate with a combination of the load against the conveyor and the reference load against the weighing system, comparing the test load stimulus with the load stimulus, and adjusting the weighing system if the comparison of the load stimulus and the test load stimulus is unacceptable. Preferably, a load cell generates the test load stimulus, and a controller carries out the comparison and adjusting tasking events. However, these events can be carried out manually if desired.